Optical beam combining system and laser system

Abstract

This application provides an optical beam combining system and a laser system. The optical beam combining system includes: a superlens array comprising multiple superlens structures; a metasurface array comprising multiple metasurface structures, wherein the number of metasurface structures is the same as the number of superlens structures, and each superlens structure forms an optical path branch with one metasurface structure; and an optical beam combining structure for combining the light from multiple optical path branches into a single output beam. Through the above-described optical beam combining system, continuous phase modulation can be achieved to achieve the effect of optical beam combining.

Description

Technical Field

[0001] This application relates to the field of laser technology, and more specifically, to an optical beam combining system and a laser system. Background Technology

[0002] Existing diffractive optical devices cannot simultaneously achieve high-precision phase modulation and low crosstalk, resulting in a deterioration in the beam factor after beam combining. Summary of the Invention

[0003] The purpose of this application is to provide a beam combining system and a laser system that can achieve continuous phase modulation to achieve spatial beam combining of multiple beams in space and better maintain the quality of the beam factor.

[0004] In a first aspect, the present invention provides an optical beam combining system, comprising: a superlens array, the superlens array including multiple superlens structures; a metasurface array, the metasurface array including multiple metasurface structures, wherein the number of metasurface structures is the same as the number of superlens structures, wherein each superlens structure and a metasurface structure form an optical path branch; and an optical beam combining structure for combining the light from multiple optical path branches into a single beam for output.

[0005] In the above implementation, the output laser beam can first be collimated by a superlens, then deflected by a metasurface structure, and finally multiple laser beams can achieve spatial beam combining by an optical path combining structure.

[0006] In an optional embodiment, the superlens structure comprises multiple unit cell structures; the unit cell structures of the superlens structure are periodically arranged according to the transmission phase arrangement.

[0007] In the above implementation, the required phase modulation can be achieved by periodically arranging the cell structure, thereby adjusting the laser beam to the required state and better maintaining the quality of the beam factor.

[0008] In an optional embodiment, the metasurface structure comprises multiple unit cell structures; the unit cell structures of the metasurface structure are arranged periodically in a rectangular array.

[0009] In an optional embodiment, the unit cell structures within one period of the unit cell structure are arranged with equal phase gradients from 0 to 2π.

[0010] In the above implementation, cylinders of different radii are arranged with equal phase gradients within the same period to achieve phase coverage from 0 to 2π, thereby realizing the abnormal deflection phase of the beam corresponding to the phase gradient arrangement.

[0011] In the above implementation method, the laser beam is combined while the phase of the optical wave is continuously controlled from 0 to 2π, thereby improving the beam quality of the optical beam and mitigating the power limitation caused by the optical beam combination.

[0012] In an optional embodiment, the metasurface array includes one or more groups of metasurface structures, each group of metasurface structures contains two metasurface structures, the two metasurface structures in each group of metasurface structures are symmetrically arranged, and the phase arrangement of the two metasurface structures in each group of metasurface structures is also symmetrical.

[0013] In the above implementation method, symmetrical arrangement of metasurface structures within the group can deflect laser beams passing through the metasurface structures within the group towards a closer direction, thereby achieving beam combining more accurately.

[0014] In an optional embodiment, the optical path beam combining structure includes multiple orientation adjustment modules, and the number of orientation adjustment modules of the optical path beam combining structure is the same as the number of metasurface structures in the metasurface array.

[0015] In an optional implementation, the cell structure contained in the orientation adjustment module is the same as the cell structure contained in one of the metasurface structures in the metasurface array.

[0016] In an optional embodiment, the period of the superlens structure and the metasurface structure is in the range of 700 nm to 900 nm, and the height of the cell structure of the superlens structure and the metasurface structure is in the range of 700 nm to 900 nm.

[0017] In an optional embodiment, the materials of the superlens array, the metasurface array, and the optical path beam combiner are all dielectric materials.

[0018] In the above implementation, each structure is made of all-dielectric material, which can reduce losses and improve the beam combining efficiency of spatial light.

[0019] Secondly, the present invention provides a laser system comprising: a light beam combining system as described in any one of the foregoing embodiments and a laser array; wherein the number of lasers included in the laser array is the same as the number of superlens structures in the superlens array. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the light beam combining system provided in the embodiments of this application;

[0022] Figure 2 A schematic diagram illustrating the interaction between the optical beam combining system and the laser array provided in the embodiments of this application;

[0023] Figure 3 A schematic diagram of a superlens structure in an example provided in this application embodiment;

[0024] Figure 4 A schematic diagram of a metasurface structure in an example provided in this application embodiment;

[0025] Figure 5 A schematic diagram of the phase profile obtained when a laser beam undergoes angular deflection under the action of a metasurface structure, as provided in an embodiment of this application;

[0026] Figure 6 A schematic diagram of the optical path beam combining structure in one example provided in this application embodiment;

[0027] Figure 7 A schematic diagram showing the transmittance and phase relationship of a square cell array at different radii, provided in an embodiment of this application.

[0028] Figure 8 Scanning electron microscope image of a superlens fabricated using micro / nano fabrication technology, provided for embodiments of this application;

[0029] Figure 9 This is a schematic diagram of the structure of a laser system provided in an embodiment of this application.

[0030] Icons: 100 - Optical beam combining system; 110 - Metalens array; 111 - First metalens structure; 112 - Second metalens structure; 120 - Metasurface array; 121 - First metasurface structure; 122 - Second metasurface structure; 130 - Optical beam combining structure; 200 - Laser system; 210 - Laser array; 211 - First laser; 212 - Second laser. Detailed Implementation

[0031] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0032] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0033] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this application.

[0034] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] With the widespread application of high-power laser technology in fields such as optical communication and lidar, the demand for precise control of laser beams is increasing. Beam collimation, deflection, and beam combining, as core functional modules, directly affect the system's output power, accuracy, and energy utilization. Laser beam combining technology, as a core means to improve the output power and beam quality of high-power laser systems, faces the dual challenges of integration and performance enhancement. Traditional optical beam combining achieves multi-beam superposition through spatial filters, diffractive optical elements, or microlenses, which is difficult to achieve in terms of chip-based and lightweight design. Furthermore, microlens arrays have low fill factors, and thermal expansion of materials at high power can easily lead to wavefront distortion. In addition, existing diffractive optical devices struggle to simultaneously achieve high-precision phase modulation and low crosstalk, resulting in a deterioration in the beam factor after beam combining.

[0036] To address the aforementioned technical challenges, proposals have been made to improve the performance of individual components by optimizing optical elements (such as microlens arrays and adaptive mirrors) or introducing partial feedback mechanisms. However, these proposals still do not solve the problems of multi-module collaborative control and system-level optimization.

[0037] Based on the above research, this application provides an optical beam combining system 100 and a laser system 200, which can improve the above-mentioned problems. Some embodiments are described below.

[0038] Figure 1 This is a schematic diagram of the structure of the optical beam combining system 100 provided in an embodiment of this application. Figure 1 As shown, the optical beam combining system 100 includes: a superlens array 110, a metasurface array 120, and an optical path beam combining structure 130.

[0039] The superlens array 110 may include multiple superlens structures; the metasurface array 120 may include multiple metasurface structures.

[0040] The number of metasurface structures is the same as the number of superlens structures, for example, such as Figure 1 As shown, if the number of superlens structures in the superlens array 110 is two, then the number of metasurface structures in the metasurface array 120 is also two; for example, as... Figure 2 As shown, the number of superlens structures in the superlens array 110 is four, and the number of metasurface structures in the metasurface array 120 is also four. It is understandable that the number of superlens structures in the superlens array 110 can be appropriately selected based on the needs of actual application scenarios. Figure 1 In the example shown, the number of superlens structures in the superlens array 110 is two, and the number of metasurface structures in the metasurface array 120 is also two. In practice, there can be even more superlens structures, with each pair of superlens structures forming a group and arranged side by side.

[0041] Each superlens structure and a metasurface structure form an optical path branch. Figure 1 In the example shown, it can form two optical paths, which are finally combined into a single beam of light through the optical path combining structure 130. Figure 2 In the example shown, it can form four optical path branches, which are finally combined into a beam of light through the optical path combining structure 130.

[0042] Optionally, unit cell structures can be arranged on the superlens structure and metasurface structure, and these unit cell structures can be arranged periodically. For example, each unit cell structure can be a cylinder of different radii, and these cylinders can be arranged in a periodic row. Each unit cell structure can be a cube structure of different sizes, or other polarization-independent structures.

[0043] For example, the cylindrical array of the superlens structure can be arranged in a transmission phase arrangement, and the cylindrical array of the metasurface structure can be arranged in a rectangular lattice array.

[0044] The optical path combining structure 130 can be used to combine the light from multiple optical path branches into a single beam for output.

[0045] Under the action of the superlens structure, the laser beam passing through the superlens can be collimated; under the action of the metasurface structure, the laser beam is deflected at a certain angle; finally, under the action of the optical path combining structure 130, the laser beams through each optical path branch are combined into a single laser beam.

[0046] In this embodiment, based on the superlens structure and metasurface structure, divergent laser beams can be converged together, and then combined with the optical path beam combining structure 130, the divergent laser beams can be converged into a single laser beam.

[0047] In one alternative embodiment, the superlens structure comprises multiple unit cell structures; the unit cell structures of the superlens structure are periodically arranged according to the transmission phase arrangement.

[0048] Optionally, the unit cell structure can be a cylindrical structure. The cylindrical structures of this superlens structure are arranged periodically. Based on practical needs, silicon cylinders with different phase differences can be selected as a periodic unit cell structure.

[0049] In one alternative embodiment, the metasurface structure comprises multiple cell structures; the cell structures of the metasurface structure are arranged periodically in a rectangular array.

[0050] For example, the metasurface structure can be formed in multiple columns to form a period, with each column having the same parameters. For instance, each M columns form a period, and the parameters of the first column's unit structure are the same as those of the (M+1)th column's unit structure. Here, M is a positive integer greater than one.

[0051] In this embodiment, the metasurface structure uses silicon cylinders with different phase differences as periodic unit cells. According to the generalized refractive index law, a unit cell structure with the desired angular deflection effect can be selected. By changing the parameters of the unit cell structure, such as its height and radius, the transmittance and phase can be controlled.

[0052] like Figure 3 As shown, Figure 3 A schematic diagram of a superlens structure in one example is shown. Figure 3 In the example shown, the cylindrical cells with radii of d = 100 nm, d = 155 nm, d = 166 nm, d = 174 nm, d = 182 nm, and d = 198 nm within one period of the superlens structure are arranged in a phase-arranged manner, with a height h of 800 nm for each cell. By controlling the phase distribution of the scattered light emitted by the laser, the divergent light wave is adjusted to a plane wavefront, thereby achieving beam collimation.

[0053] In an alternative embodiment, the cell structures of the metasurface structure are arranged with equal phase gradients from 0 to 2π within one period of the cell structure.

[0054] In this embodiment, the cell structure on the metasurface structure can be a cylindrical array structure. Each cylindrical array structure can be a periodic arrangement of cylinders with different radii on the substrate. In one example, the radius distribution of a period of cylinders can be... d = 100 nm d = 155 nm d = 166 nm d = 174 nm d = 182 nm d =198 nm. In this example, every six columns form a period, and the parameters of the unit cell structure of the first column are the same as those of the seventh column.

[0055] For example, the cylindrical array structure on the superlens structure and metasurface structure can be formed by patterning the structure on a substrate using electron beam lithography, then depositing it on the lithographically defined nanopattern using electron beam evaporation, using chromium metal as a hard mask material, and finally performing dry etching using reactive ion etching technology to form a high aspect ratio nanostructure. The aspect ratio of the high aspect ratio nanostructure can be in the range of 1:4 to 1:2.

[0056] like Figure 4 As shown, Figure 4 A schematic diagram of a metasurface structure in an example is shown. Figure 4 In the example shown, the cell structure of the metasurface is periodically arranged in a rectangular array. This periodic arrangement of the rectangular array allows for the construction of a phase gradient distribution at the subwavelength scale, ensuring strict consistency in the phase gradient direction and forming a continuous phase change. Figure 4 In the example shown, the first six columns are different nanopillars corresponding to equal gradient phases from 0 to 2π. Therefore, arranging them in a periodic equal gradient manner can achieve beam deflection, change the propagation direction of the incident light wavefront, and achieve high-efficiency beam deflection.

[0057] Optionally, the metasurface array 120 may include one or more groups of metasurface structures, each group comprising two metasurface structures. The two metasurface structures in each group are symmetrically arranged, and the phase arrangement of the two metasurface structures in each group is also symmetrical. For example, the symmetry points of each group of metasurface structures may coincide.

[0058] Optionally, if the metasurface array 120 includes two metasurface structures, the metasurface array 120 may include a first metasurface structure 121 and a second metasurface structure 122.

[0059] Along the first direction, the unit cell structure of the first metasurface structure 121 is arranged with equal phase gradients from 0 to 2π within one period; along the first direction, the unit cell structure of the second metasurface structure 122 is arranged with equal phase gradients from 2π to 0 within one period.

[0060] This first orientation can vary depending on the placement of the metasurface structure. Figure 1 In the example shown, the first direction is the top-to-bottom direction as illustrated.

[0061] by Figure 4 Taking the example shown, the first metasurface structure 121 can be... Figure 4 The second metasurface structure 122 can be arranged as shown in the diagram. Figure 4 The state shown is the arrangement after rotating 180°.

[0062] like Figure 5 As shown, Figure 5 This illustration shows a phase profile of a laser beam, as provided in an embodiment of this application, undergoing angular deflection under the influence of a metasurface structure. The X-axis represents the position of the superlens structure, and the Z-axis represents the position of the laser beam in space after penetrating the metasurface structure. Figure 5 As can be seen, the phase of the horizontal wave vector of the laser beam along the positive Z-axis changes after passing through the metasurface structure, thus achieving beam deflection.

[0063] Optionally, if the metasurface array 120 includes four metasurface structures, the metasurface array 120 may include a first metasurface structure, a second metasurface structure, a third metasurface structure, and a fourth metasurface structure.

[0064] The first metasurface structure, along a first direction, has its cell structures arranged with an equal phase gradient from 0 to 2π within one period. The second metasurface structure, along the first direction, also has its cell structures arranged with an equal phase gradient from 2π to 0 within one period. The third metasurface structure, along a second direction, has its cell structures arranged with an equal phase gradient from 0 to 2π within one period. The fourth metasurface structure, along the second direction, also has its cell structures arranged with an equal phase gradient from 2π to 0 within one period. The first and second directions can form an angle; for example, they can be perpendicular. Exemplarily, the first and second metasurface structures are symmetrically arranged, as are the third and fourth metasurface structures, and the first and second metasurface structures are represented as a first point of symmetry, while the third and fourth metasurface structures are represented as a second point of symmetry, with the first and second points of symmetry coinciding.

[0065] Optionally, if the metasurface array 120 includes four metasurface structures, the metasurface array 120 may include a first metasurface structure, a second metasurface structure, a third metasurface structure, a fourth metasurface structure, a fifth metasurface structure, and a sixth metasurface structure.

[0066] The first metasurface structure, along the first direction, has its cell structures arranged with an equal phase gradient from 0 to 2π within one cycle. The second metasurface structure, along the first direction, also has its cell structures arranged with an equal phase gradient from 2π to 0 within one cycle. The third metasurface structure, along the second direction, has its cell structures arranged with an equal phase gradient from 0 to 2π within one cycle. The fourth metasurface structure, along the second direction, has its cell structures arranged with an equal phase gradient from 2π to 0 within one cycle. The fifth metasurface structure, along the third direction, has its cell structures arranged with an equal phase gradient from 0 to 2π within one cycle. The sixth metasurface structure, along the third direction, has its cell structures arranged with an equal phase gradient from 2π to 0 within one cycle. The first, second, and third directions can form certain angles; for example, the first and second directions can form a 60° angle, and the second and third directions can also form a 60° angle.

[0067] For example, the first metasurface structure and the second metasurface structure are arranged symmetrically, the third metasurface structure and the fourth metasurface structure are arranged symmetrically, and the fifth metasurface structure and the sixth metasurface structure are arranged symmetrically. The first metasurface structure and the second metasurface structure are represented as a first point of symmetry, the third metasurface structure and the fourth metasurface structure are represented as a second point of symmetry, and the fifth metasurface structure and the sixth metasurface structure are represented as a third point of symmetry, and the first point of symmetry, the second point of symmetry, and the third point of symmetry coincide.

[0068] In an optional embodiment, the optical path combining structure 130 includes multiple direction adjustment modules. The number of direction adjustment modules in the optical path combining structure is the same as the number of metasurface structures in the metasurface array. Each direction adjustment module corresponds to one of the metasurface structures and is used to adjust the optical path output by its corresponding metasurface structure, thereby combining the optical paths output by each metasurface structure into a single beam in one direction.

[0069] like Figure 6 As shown, Figure 6 A schematic diagram of an optical path combining structure 130 in one example is shown. Figure 6 The example shown illustrates a configuration containing only two orientation adjustment modules. The left half represents the first orientation adjustment module, and the right half represents the second orientation adjustment module, which is the state after the first orientation adjustment module has been rotated 180°. Optionally, the optical path combining structure 130 can be formed by splicing two identical metasurface structures adjacent to each other. One of the metasurface structures is rotated 180°, making the optical path combining structure 130 a centrally symmetrical structure. After the laser beams from the symmetrical incident directions (i.e., the laser beams output from the first metasurface structure 121 and the second metasurface structure 122) pass through the symmetrical optical path combining structure 130, their phase gradients are adjusted to the same output direction, thus achieving beam combining.

[0070] Optionally, the first direction adjustment module can be used to adjust the direction of the laser beam passing through the optical path branch where the first metasurface structure 121 is located, and the second direction adjustment module can be used to adjust the direction of the laser beam passing through the optical path branch where the second metasurface structure 122 is located. For example, the first direction adjustment module and the first metasurface structure 121 can deflect the laser beam in opposite directions, so that after the laser beam passes through the first metasurface structure 121 and the first direction adjustment module sequentially, if the laser beam was horizontal before passing through the first metasurface structure 121, it will still remain horizontal after passing through the first metasurface structure 121 and the first direction adjustment module. Similarly, the second direction adjustment module and the second metasurface structure 122 can deflect the laser beam in opposite directions, so that after the laser beam passes through the second metasurface structure 122 and the second direction adjustment module sequentially, if the laser beam was horizontal before passing through the second metasurface structure 122, it will still remain horizontal after passing through the second metasurface structure 122 and the second direction adjustment module.

[0071] In this embodiment, the superlens array 110 may also include a first superlens structure 111 and a second superlens structure 112. The two laser beams passing through the first superlens structure 111 and the second superlens structure 112 can be parallel beams. After the two parallel laser beams pass through the first metasurface structure 121 and the second metasurface structure 122 respectively, the direction of the laser beams can be deflected. For example, the two laser beams that are deflected after passing through the first metasurface structure 121 and the second metasurface structure 122 can converge to the same position of the optical path beam combining structure 130. For details, please refer to... Figure 1 As shown, the laser beam located at the top of the diagram can be deflected downwards, while the laser beam located at the bottom of the diagram can be deflected upwards.

[0072] In this embodiment, the first metasurface structure 121 controls the deflection angle of the laser beam, and the distance between the optical path combining structure 130 and the first metasurface structure 121 can be set based on actual needs. The deflection angle of the laser beam and the distance between the optical path combining structure 130 and the first metasurface structure 121 can be set in conjunction. After the laser beam output from the first superlens structure 111 is deflected by the first metasurface structure 121, the distance between the optical path combining structure 130 and the first metasurface structure 121 can reach the middle region of the optical path combining structure 130.

[0073] In this embodiment, the second metasurface structure 122 controls the deflection angle of the laser beam, and the distance between the optical path combining structure 130 and the second metasurface structure 122 can be set based on actual needs. The deflection angle of the laser beam and the distance between the optical path combining structure 130 and the second metasurface structure 122 can be set in conjunction. After the laser beam output from the second metalens structure 112 is deflected by the second metasurface structure 122, it can reach the middle region of the optical path combining structure 130 after passing through the distance between the optical path combining structure 130 and the second metasurface structure 122.

[0074] Optionally, the cell structure included in the first orientation adjustment module is the same as the cell structure included in one of the metasurface structures in the metasurface array 120. The cell structure included in the second orientation adjustment module may be similar to the cell structure included in the first orientation adjustment module, except that the layout of the cell structure included in the second orientation adjustment module is the same as the structure of the cell structure included in the first orientation adjustment module after rotating it by 180°.

[0075] exist Figure 2 In the example shown, the optical path combining structure 130 can be formed by projecting the positions of the various metasurface structures in space onto a plane based on the metasurface array 120. In this example, the structural size of the optical path combining structure 130 is four times that of the metasurface structure.

[0076] Optionally, the period of the superlens structure and the metasurface structure is in the range of 700 nm to 900 nm, and the height of the cell structure of the superlens structure and the metasurface structure is in the range of 700 nm to 900 nm.

[0077] For example, the period of the superlens structure and the metasurface structure can be one of the following values: 700nm, 750nm, 800nm, 850nm, 900nm, etc.

[0078] For example, the height of the cell structure of the superlens structure and the metasurface structure can be one of the values ​​of 700nm, 750nm, 800nm, 850nm, 900nm, etc.

[0079] In one example, the period of the superlens structure and the metasurface structure, as well as the height of the cell structure, can both be 800 nm.

[0080] Optionally, the superlens array 110, the metasurface array 120, and the optical path combining structure 130 are made of all-dielectric materials.

[0081] For example, the all-dielectric material can be silicon (Si), titanium dioxide (TiO2), gallium nitride (GaN), silicon nitride (SiN), etc.

[0082] In one example, the light beam combining system 100 may include two identical superlens structures, two metasurface structures, and a symmetrical metasurface structure. The metasurface structure can be composed of a periodic array of cylinders of different radii arranged on a quartz substrate, and can be fabricated using etching techniques such as electron beam lithography, electron beam evaporation, and reactive ion deposition for spatial light beam combining. Simulation results of the above example show that by selecting silicon cylinders with different phase differences as periodic unit cells, beam deflection can be achieved according to the generalized refractive index law; by changing the height and radius of the silicon cylinders, transmittance and phase can be controlled. The light beam combining system 100 provided in this application embodiment has high integration, low loss, and can achieve continuous phase control, showing good application prospects in integrated optical systems, multispectral imaging, and intelligent sensing devices.

[0083] In this embodiment of the application, in order to select a more suitable metasurface structure, the transmittance and phase relationship of the square cell array structure at different radii were studied.

[0084] Figure 7 This is another example of the transmittance and phase relationship of a square lattice array structure at different radii provided in this application embodiment. Numerical calculations were performed using the finite-difference time-domain method. At a wavelength of 1550 nm, the transmittance coefficient and phase of the periodic nanopillars were analyzed by varying the radius of the cylinders from 100 nm to 260 nm. In the calculations, the refractive index of the silicon cylinder was 3.47, the height was fixed at 800 nm, the refractive index of the quartz substrate was 1.45, and the thickness was 2 μm. Figure 7 It can be observed that by changing the radius of the silicon cylinder (100 ~ 260 nm), the device can obtain a large transmission amplitude in the full phase range of 0-2π. Within the range of cylinder radius of 100~260 nm, the transmittance of the device remains above 95%. Figure 7 In the example shown, the horizontal axis represents the radius, and the vertical axis includes transmittance and phase, respectively.

[0085] In this embodiment of the application, the structure of each device in the optical beam combining system 100 provided in this embodiment of the application can be designed by the finite-difference time-domain method.

[0086] For example, the effect of changes in device structural parameters on transmittance and phase can be analyzed, and the phase relationship corresponding to different radii can be obtained through simulation. Specifically, this can be done as follows: Figure 7As shown. Then, for the rectangular substrate and the cylindrical structure placed on the substrate, the corresponding material refractive indices can be added respectively. The simulation region is added as one unit cell period. A light source is added to the substrate, and a point monitor and a surface monitor are added above the structure to monitor the phase change and transmittance of the light source after passing through the structure. The parameter scan is performed by changing the size of the cylinder radius. By running the simulation, the relationship between the radius and the phase can be obtained through the monitor. Generally, as the radius increases, the phase changes from 0 to 2π.

[0087] In this embodiment, the parameters of each unit cell structure can be designed using the generalized law of refraction (also known as Snell's law). According to Snell's law: To calculate the diffraction angle of the gradient surface. ,in and It is the refractive index of the surrounding medium on both the transmission and incident sides. Indicates the angle of incident light. Indicates the wavelength of vacuum. This represents the phase gradient. Based on Snell's law, cylinders of different radii can be arranged with an equal phase gradient within the same period to achieve phase coverage from 0 to 2π, thus realizing the abnormal beam deflection phase corresponding to this phase gradient arrangement. In this embodiment, the phase distribution of the superlens can be determined according to the divergence angle of the light source, the phase can be discretized, and cylinders with corresponding phases can be arranged on the corresponding grid to construct the corresponding superlens.

[0088] Taking the periodic array structure as the research object, a spatial beam combining system 100 for semiconductor laser array 210 can be obtained. The schematic diagram of the whole system is shown below. Figure 1 As shown. The cell structure of the superlens structure in the superlens array 110 can be composed of nanocylinders, whose lattice constant is consistent with that of the simulated cylinder. The lens is meshed with the center at (0, 0). According to the phase distribution formula of a circular lens: Substitute the required focal length and target wavelength to calculate the corresponding grid position on the lens. The phase of the lens is determined by placing cylinders of the corresponding radius in the corresponding region. Since the phase arrangement of the lens follows a phase gradient, beam convergence can be achieved. The scattered light emitted from the laser placed at the focal point of the superlens structure passes through the superlens structure simultaneously. Due to the focusing characteristics of the superlens, the scattered light emitted from the focal point is collimated into parallel light after passing through the superlens and then focused onto the metasurface structure. After passing through the metasurface structure, the laser beam undergoes a certain angle of deflection. The metasurface structure is a large-area periodic metasurface consisting of cylinders with a phase gradient of 0 to 2π arranged in a period. According to Snell's law, arranging cylinders of different radii with an equal phase gradient within the same period achieves phase coverage from 0 to 2π, thus realizing the abnormal deflection phase of the beam corresponding to this phase gradient arrangement. In this embodiment, the first metasurface structure 121 can achieve phase coverage from 0 to 2π, realizing the abnormal deflection phase of the laser beam. The second metasurface structure 122 can achieve beam deflection at the opposite angle by arranging cylinders with a reverse equal gradient from 2π to 0. After passing through the metasurface structure, the laser beam is focused onto the optical beam combining structure 130 with a symmetrical structure. After passing through the optical beam combining structure 130, the laser beams from multiple branches are combined into a single laser beam, realizing the beam combining function of spatial light.

[0089] In this embodiment, as Figure 8 As shown, Figure 8 A scanning electron microscope image of a superlens fabricated using micro-nano fabrication technology, provided for an embodiment of this application. Figure 8 The example shown only illustrates a partial structural schematic of the superlens structure. In this embodiment, the corresponding GDS pattern can be first drawn using Matlab for fabrication. After cleaning and drying the quartz substrate, the designed metasurface nanostructure pattern is fabricated on the substrate using electron beam lithography. The main process for drawing the nanostructure pattern can include steps a1 to c1.

[0090] a1. Spin-coating photoresist (EB200). Spin-coating speed 3000 rpm, time 1 min, film thickness approximately 200 nm, baking at 180°C for 90 s to remove solvent.

[0091] The parameters for spin-coating photoresist described above are merely illustrative and can be adjusted to suit specific needs. Since the spin-coating speed only affects the resist thickness, a speed range of 2000 rpm to 5000 rpm can achieve film thicknesses of 100 nm to 250 nm. In practical applications, the appropriate spin-coating speed can be selected based on the desired film thickness.

[0092] b1. Exposure: The drawn pattern is exposed using an electron beam exposure system with an accelerating voltage of 100 kV and an exposure dose of approximately 200 μC / cm². 2 .

[0093] Insufficient exposure will result in incomplete graphic display, while excessive exposure will cause graphics from adjacent periods to overlap. The exposure doses provided above are merely illustrative; the exposure dose in this application embodiment can be determined based on actual testing. Optionally, the exposure dose can also be 180 μC / cm². 2 -300μC / cm 2 A value within the range.

[0094] c1. Development and fixing: Develop in developer for 60 seconds.

[0095] A shorter development time will result in an incompletely displayed image, while a longer time will slightly enlarge the image. Therefore, the development process can be monitored in real time, and the development time adjusted accordingly.

[0096] Finally, rinse with clean water and dry with N2 air.

[0097] Materials are deposited using electron beam evaporation on nanopatterns defined by photolithography, facilitating subsequent etching to form metasurface structures. Cr or Ni metal is selected as the hard mask material based on its physicochemical properties. The deposition process may include steps a2 to d2.

[0098] a2. Vacuum pretreatment: The substrate is placed in an electron beam evaporation system, with a vacuum level of 10. -6 Torr.

[0099] b2. Material deposition: Control the deposition rate (1-2 A / s) to ensure film uniformity.

[0100] c2. Improve adhesion: Deposit 3-5 nm Ti as an adhesion layer in front of the metal layer.

[0101] d2. Lift-off: Immerse the sample in acetone and sonicate for 10 minutes to remove areas without attached metal. The cleaning effect can be observed; if metal areas are not removed, the ultrasonic cleaning time can be increased.

[0102] Each component of the optical beam combining system 100 can be manufactured according to the process described above, from steps a1 to c1 and from steps a2 to d2.

[0103] In this embodiment, if the required number of lasers in the laser array is large, the deflection angle is mainly determined by the design of the metasurface structure. It is calculated using the generalized refractive index law, and the deflection angle can be varied by changing the phase difference. When the beam deflection exceeds 30°, efficiency may decrease. This can be addressed by optimizing the metasurface structure parameters or using a meta-grating, thereby achieving large-angle, high-efficiency deflection and beam combining. The arrangement of multiple metasurface structures can be determined by the deflection angle they form on the optical path and the distance between two metasurface structures. The distance can be calculated using the formula L=Dtanθ, where L represents the distance of the metasurface structure from the center of the metasurface array, D represents the distance between the plane containing the metasurface array and the plane containing the beam combining structure, and θ represents the deflection angle formed by the metasurface structure on the optical path.

[0104] Based on the above design concept and manufacturing process, the optical beam combining system 100 achieves efficient linkage of collimation, deflection and beam combining functions, which can improve the overall accuracy, stability and applicability of beam control.

[0105] This application also provides a laser system 200, such as... Figure 9 As shown, the laser system 200 may include: an optical beam combining system 100 and a laser array 210.

[0106] exist Figure 9 In the example shown, laser array 210 contains two lasers. The superlens array 110 also has two superlens structures, and the metasurface array 120 also has two metasurface structures, namely a first laser 211 and a second laser 212.

[0107] Alternatively, the laser array 210 may also include a greater number of lasers (such as...). Figure 2 As shown in the figure, the number of superlens structures in the superlens array 110 and the number of metasurface structures in the metasurface array 120 can also be more, the same as the number of lasers in the laser array 210.

[0108] The number of lasers in laser array 210 is the same as the number of superlens structures in superlens array 110.

[0109] The optical beam combining system 100 provided in this application embodiment can be the same as the optical beam combining system 100 provided in the foregoing embodiments. Other details about the optical beam combining system 100 in this embodiment can be found in the descriptions in the foregoing embodiments, and will not be repeated here.

[0110] In this embodiment, a metasurface is incorporated, allowing manipulation of the light wavefront by altering the phase, amplitude, or polarization of the light wave at the subwavelength scale. The metasurface structure overcomes the diffraction limit's constraint on device size, enabling smaller scale and higher precision beam control. Furthermore, both the superlens structure and the metasurface structure in this embodiment utilize all-dielectric materials, reducing losses and improving the beam combining efficiency of spatial light. This allows for multi-functional coordinated control of phase, deflection, and energy, overcoming the limitations of traditional optical systems in terms of efficiency, size, and flexibility. Integrating a nanoscale coupling alignment system onto the superlens structure and metasurface structure enables rapid and precise alignment of the fiber and laser, exhibiting high coupling efficiency.

[0111] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0112] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A light beam combining system, characterized in that, include: A superlens array, wherein the superlens array comprises multiple superlens structures; A metasurface array comprising multiple metasurface structures, wherein the number of metasurface structures is the same as the number of superlens structures, and wherein each superlens structure and a metasurface structure form an optical path branch; The metasurface structure comprises multiple unit cell structures; the unit cell structures of the metasurface structure are arranged periodically in a rectangular array, and the unit cell structures within one period are arranged with equal phase gradients from 0 to 2π. The unit cell structures of the metasurface structure are cylindrical, and the radii of the cylinders are distributed between 100 nm and 198 nm. Every six columns form one period, and the radii of the cylinders in one period are d=100 nm, d=155 nm, d=166 nm, d=174 nm, d=182 nm, and d=198 nm. The arrangement of the multiple metasurface structures is determined by the deflection angle they form on the optical path and the distance between the metasurface structures; The distance between multiple metasurface structures is given by the formula: L=Dtanθ; L represents the distance between the metasurface structure and the center of the metasurface array; D represents the distance between the plane where the metasurface array is located and the plane where the optical path beam combining structure is located; θ represents the deflection angle formed by the metasurface structure on the optical path; wherein, in use, the cell structure of the metasurface structure with the required angle of deflection is selected according to the generalized refractive index law to determine the deflection angle formed on the optical path. An optical path combining structure is used to combine the light from multiple optical path branches into a single beam for output. The optical path beam combining structure includes multiple direction adjustment modules, and the number of direction adjustment modules of the optical path beam combining structure is the same as the number of metasurface structures in the metasurface array. The optical paths output by each metasurface structure are combined into one beam in one direction through each direction adjustment module.

2. The light beam combining system according to claim 1, characterized in that, The superlens structure comprises multiple unit cell structures; The cell structure of the superlens is arranged periodically according to the transmission phase arrangement.

3. The light beam combining system according to claim 1, characterized in that, The metasurface array includes one or more groups of metasurface structures. Each group of metasurface structures contains two metasurface structures. The two metasurface structures in each group of metasurface structures are symmetrically arranged, and the phase arrangement of the two metasurface structures in each group of metasurface structures is also symmetrical.

4. The light beam combining system according to claim 1, characterized in that, The cell structure contained in the orientation adjustment module is the same as the cell structure contained in one of the metasurface structures in the metasurface array.

5. The light beam combining system according to any one of claims 1-4, characterized in that, The period of the superlens structure and the metasurface structure is in the range of 700nm to 900nm, and the height of the cell structure of the superlens structure and the metasurface structure is in the range of 700nm to 900nm.

6. The light-combining system according to any one of claims 1-4, characterized in that, The materials of the superlens array, the metasurface array, and the optical path beam combiner are all dielectric materials.

7. A laser system, characterized in that, include: The optical beam combining system and laser array according to any one of claims 1 to 6 above; The number of lasers in the laser array is the same as the number of superlens structures in the superlens array.

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